Large amounts of algae were collected from the surface of the Texcoco Lake water. High in protein, this algae (known as tecuitlatl) was used to make bread and cheese type foods. This algae is still used in Mexico as a fertilizer.
The Aztecs often cooked food bundled in the Maguey plant leaves. This dish is called Mixiotes, and it's still eaten in Mexico today. Different leaves are used because the Maguey population was suffering.
Chocolate
One of the greatest gifts to the world from Mexico is chocolate. The cocoa bean was highly treasured in the Aztec Empire. In fact, the bean was used as a currency, as well as Aztec food. Or, in this case, drink.
The cocoa beans were used to make a thick chocolate drink, but far different than the hot chocolate we know today. Since they didn't use sugar, the Mexicas added peppers, corn meal and spices. A similar hot drink is still found in Mexico today with corn, known as atole.
Though Columbus brought cocoa to Europe in the early 1500s, it was mostly ignored. Hernan Cortes was more interested, and substituted sugar and vanilla for the spices. It became a commercial success.
The word chocolate even comes from an Aztec/Mayan word chocolatl.
Chocolate actually may have played a part in the fall of the Aztec empire. The Aztecs believed that the god Quetzalcoatl brought the cocoa beans from the tree of life to give to man. Later, the god was banished. It seems that at first the Mexicas believed that Hernan Cortes, the Spanish conquerer, was their returning god.
Aztec food recipes
There are some excellent recipes available online. Find a low carb Mixiotes recipe here. There's also a recipe for atole. cdkitchen.com has a unique hot chocolate recipe, a combination of Aztec and Spanish traditions.
For more Aztec recipes, try a search at cooks.com. Of course, not all of these are real authentic Aztec food, but after reading this article you should have an idea what common elements are in Aztec cooking. For more on traditional Mexican food and what came from the Aztecs, check here. By the way, we know the Aztecs didn't eat chicken, but just for fun here's an Aztec chicken recipe...